The latest data from the North
Carolina website indicates the frequency of samples testing positive
for H1N1 has risen to 25% (see Figure 2)
from a low of 8% in December. The frequency has not been at 25%
since mid-November. This clear upswing in H1N1 detection is
consistent with recent comments on increases on college
campuses in North Carolina and reports of more severe cases at UNC
Medical Center at Chapel Hill. This rise signals the start of
wave three.

Flu levels in North Carolina have been a concern because of the fatal
cluster at Duke
Medical Center last October. Tamiflu resistant H1N1 was
transmitted patient to patient and at least 3 of the patients
died. Recently released sequences from North Carolina indicate
five patients were Tamiflu resistant and had the rare HA marker of
Y233H. Moreover, 3 of the HA sequences had D225G
or D225N, demonstrating transmission of the receptor binding domain
changes strongly linked to fatal cases. The presence of D225G/N
in the Duke death cluster was not
disclosed in a WHO
report on the outbreak, or in subsequent reports on D225G by the ECDC
or WHO. In
addition to these three cases, another isolate collected in the same
time frame, but matching the sub-clade from Ukraine
also had D225G, signaling significant levels of D225G in the area.

The increases in D225G/N in North Carolina has led to concerns that
D225G/N will be more common in a third wave because of its linkage to a
low
reactor status designed by Mill Hill, as well as an increase
infrequency of D225G/N reports, with highest frequencies being reported
in Ukraine and Russia.

Moreover, last week’s CDC report had a spike
in Pneumonia and Influenza deaths to 8.2%. The upcoming week 4
report will have the rate at 8.1%, confirming that the spike higher was
not due to anomalies associate with holidays. Moreover, the
upcoming week 4 report will have 9 pediatric deaths, including 6 in
California, once again raising concerns that the severity and lethality
of recent H1N1 is higher in 2010 than 2009.

Sequence data on H1N1 from area hospitals and recently detected cases
in North Carolina would be useful.